Premium Economy on the 777-300 is only worthwhile on the LHR-LAX and HKG-LHR daylight flights, where it is a lovely seat. But for overnight flights it is just hopeless: wider than you can use, but with no usable recline at all. They stuffed up big-time going 2-2-2 reclineless hard-shell on this aircraft, where all other sectors are night flights. They'd have done better to go 2-4-2 with conventional seats with triple the recline of the SpaceSeat.
Well put but you aren't going to be flying HKG-LHR on the 777-300 (at least not very often).
PE isn't bad from the perspective of giving a much better upgrade to Business chance, decent food and drinks and more space, but overall for me it isn't worth the price premium over economy - often more than double. Particularly on the 772. 77W, 744 - I will pay a premium, but not necessarily the premium requested.